As millions around the world experienced the vertiginous view from his capsule's camera, which showed a round blue world surrounded by the black of space, he stepped off into the void and plummeted for more than four minutes, reaching a maximum speed measured at 1342km/h, or Mach 1.24.

Leap of faith ... Felix Baumgartner. Photo: Reuters

Baumgartner was backed by a NASA-style mission control operation at an airfield in Roswell that involved 300 people, including more than 70 engineers, scientists and physicians who have been working for five years on the project, called Red Bull Stratos, after the drink company that has financed it.

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Besides aiming at records, the engineers and scientists on the Red Bull Stratos team have been gathering and publishing reams of data intended to help future pilots, astronauts and perhaps space tourists survive if they have to bail out.

"We're testing new spacesuits, escape concepts and treatment protocols for pressure loss at extreme altitudes," said the Red Bull Stratos medical director, Dr Jonathan Clark, who formerly oversaw the health of space shuttle crews at NASA. "There are so many things that could go wrong here that we're pushing the technical envelope."

On top of the world ... Felix Baumgartner celebrates after leaping from the edge of space. Photo: AP and Jay Nemeth/Red Bull Content Pool

While building the customised suit and capsule, the team of aerospace veterans had to contend with one crucial uncertainty: What happens to the human body when it breaks the sound barrier?

There was also one major unexpected problem for Baumgartner.

Although he had no trouble jumping off buildings and bridges, and soaring across the English Channel in a carbon-fibre wing, he found himself suffering panic attacks when forced to spend hours inside the pressurised suit and helmet.

At one point in 2010, rather than take an endurance test in it, he went to an airport and fled the United States. With the help of a sports psychologist and other specialists, he learned techniques for dealing with the claustrophobia.

One of the techniques Baumgartner developed was to stay busy throughout the ascent. He conversed steadily with Joe Kittinger, whose record he broke. The deep voice of Kittinger, a former fighter pilot, clearly exuded the right stuff as he confidently went through a 40-item checklist rehearsing every move that Baumgartner would make when it came time to leave the capsule — tasks like sliding his seat forward, checking his parachutes and carefully opening the hatch.

When the actual moment came, Kittinger said to him, "All right, step up on the exterior step. Start the cameras. And our guardian angel will take care of you now."

Daredevil ... Felix Baumgartner of Austria is watched on a screen from the mission control centre. Photo: Reuters

Baumgartner stepped outside, saluted and made the jump right after delivering a message that was mostly garbled by radio static. Afterward, he repeated it: "I know the whole world is watching, and I wish the whole world could see what I see. Sometimes you have to go up really high to understand how small you really are."

In his leap, he broke altitude and speed records set half a century ago by Kittinger, now 84, a retired Air Force colonel whose reassuring voice from mission control guided Baumgartner through tense moments.

Engineers considered aborting the mission when Baumgartner's faceplate began fogging during the ascent, but he insisted on proceeding and made plans for doing the jump blind.

That proved unnecessary, but a new crisis occurred early in the jump when he began spinning out of control in the thin air of the stratosphere — the same problem that had nearly killed Kittinger a half-century earlier. But as the atmosphere thickened, Baumgartner managed to stop the spin and fall smoothly until he opened his parachute about a mile above the ground and landed smoothly in the New Mexico desert.

Kittinger praised Baumgartner's courage for proceeding with the mission and said that he had more than broken a record.

"He demonstrated that a man could survive in an extremely high altitude escape situation," Kittinger said. "Future astronauts will wear the spacesuit that Felix test-jumped today."

When Baumgartner lost control of his body during the early part of the jump, he feared going into a flat spin that would send blood away from the center of his body.

"At a certain RPM," he said afterward, "there's only one way for blood to leave your body, and that's through your eyeballs. That means you're dead. That was what we feared most."

Because of the limited sensations he felt inside his stiff pressurised suit, he said recovering from a spin was much more difficult than during an ordinary sky dive.

"As a sky-diver, you can feel the air on your right shoulder and you immediately know what to do," he said. "Here you don't feel the air, so you have to wait until the air pushes you around. Then you think, 'Oh, it pushed me around clockwise — that means I have to do this."'

Brian Utley of the FAI, the international federation that certifies aerospace records, calculated the height and speed of the jump by independently analysing data gathered on microchips in Baumgartner's suit. After a thorough analysis of the data is made over the next several weeks, Utley said, the precise official figures might be slightly different, but he had no doubt that Baumgartner had set a supersonic speed record.

The mission required the largest balloon ever used for a manned flight. Made of 40 acres of ultrathin plastic, it had been described as an inflated dry-cleaning bag that would fill the Los Angeles Coliseum. Baumgartner rode in a capsule attached by cables, below it.

An earlier attempt to inflate the balloon and carry out the mission had to be abandoned last week because of weather. As the balloon rose in the sky, viewers from around the world went to YouTube to watch a live video stream from the capsule and mission control. By the time Baumgartner made his leap into space, the audience grew to a peak of 8 million watching at the same time, which appeared to be a record; YouTube's previous record for concurrent viewership was around half a million, set during the Summer Olympics earlier this year.

16 Oct
Felix Baumgartner stood poised in the open hatch of a capsule suspended above Earth, wondering if he would make it back alive. Thirty-eight kilometres below him, millions of people were watching on the internet and marvelling at the moment.

16 Oct
Felix Baumgartner, the world's first supersonic skydiver, has admitted he was "terrified" and feared he would black out as he spun violently out of control 39 kilometres above the Earth during his death-defying leap from the edge of space.